American railroads were one of the nation's first big businesses, and, as such, workers joined the new industrial order in its infancy. Many rail workers responded their working conditions by trying to organize themselves into unions. Most railway workers organized along craft lines. That is, people doing the same jobs like conductors banded together, rather than all the workers on the trains. Other skilled workers joined unions based on their trades: they joined unions like the machinists or boilermakers organizations. Workers who performed railroad-specific tasks, notably those done on the trains themselves, were often more successful in getting their unions recognized by employers than those workers who did jobs that were transferrable to other settings. By the 1920s, railroad workers were organized into both independent unions and into those that were affiliated with the American Federation of Labor. Craft unions in the early 20th century often excluded women and people of color from their membership rolls and most railroad unions followed the conventions of the day, restricting membership to white males.